Method for Washing and Washing Machine

ABSTRACT

A washing machine includes an outer tub and an inner tub rotatably provided in the outer tub, a spray nozzle spraying wash water into the inner tub, a circulation passage connecting the outer tub to the spray nozzle, and a filter provided in series with the circulation passage. A first pump directs the wash water from the outer tub to the circulation passage and to the spray nozzle so that foreign substances suspended in the wash water can be collected in the filter. A drain passage between the filter and spray nozzle connects the outer tub to the circulation passage. A second pump directs the wash water supplied to the circulation passage through the drain passage such that the wash water passes through the filter in a reverse direction and thus the foreign substances collected in the filter are exhausted out of the washing machine together with the wash water.

This application claims the benefit of Korean Patent Application No.10-2010-0089610 filed in Korea on Sep. 13, 2010, No. 10-2010-0112253filed in Korea on Nov. 11, 2010, and No. 10-2010-0111620 filed in Koreaon Nov. 10, 2010, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine and, moreparticularly, to a washing machine and method that collects foreignsubstances such as lint and the like suspended in wash water using afilter provided on a circulation passage when the wash water drains outof an outer tub and exhausts the collected foreign substances togetherwith the wash water out of the washing machine when draining the washwater out of the washing machine.

2. Description of the Related Art

In general, a washing machine is designed to wash the laundry usingemulsification of a detergent, water stream action generated by therotation of washing blades, and an impact action applied by the washingblades. The washing machine performs washing, rinsing, and/or spinningto remove contaminants from the laundry by using the interaction betweenthe water and the detergent.

The related art washing machine includes a lint filter for filtering outforeign substances such as lint removed from laundry. However, it istroublesome because the user cleans the lint filter. In addition, whenthe lint filter is not cleaned in a timely manner and remains in acontaminated state, mildew can grow on the filter producing a rancidsmell. Therefore, the user has to keep a close watch on the lint filterand check to determine if the lint filter is contaminated. This istroublesome for the user.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, there is provided awashing machine including: an outer tub for storing wash water; an innertub that is rotatably provided in the outer tub and in which laundry isloaded; a spray nozzle spraying the wash water into the inner tub; acirculation passage connecting the outer tub to the spray nozzle; afilter provided in series with the circulation passage; a first pumpthat directs the wash water circulated from the outer tub to thecirculation passage to the spray nozzle so that foreign substancessuspended in the wash water can be collected in the filter; a drainpassage that connects the outer tub to the circulation passage and isconnected between the filter and the spray nozzle; and a second pumpthat directs the wash water supplied to the circulation passage throughthe drain passage such that the wash water passes through the filter ina reverse direction and thus the foreign substances collected in thefilter are exhausted out of the washing machine together with the washwater.

According to another aspect of the present invention, there is provideda washing machine including: an outer tub for storing wash water; aninner tub that is rotatably provided in the outer tub and in whichlaundry is loaded; a spray nozzle spraying the wash water into the innertub; a circulation passage connecting the outer tub to the spray nozzle;a filter provided in series with the circulation passage; a drainpassage that connects the outer tub to the circulation passage and isconnected between the filter and the spray nozzle; and a pump thatdirects the wash water circulated from the outer tub to the circulationpassage such that the wash water passes through the filter in a forwarddirection and thus foreign substances suspended in the wash water can becollected in the filter or directs the wash water supplied to thecirculation passage through the drain passage such that the wash waterpasses through the filter in a reverse direction and thus the foreignsubstances collected in the filter are exhausted together with the washwater.

According to still another aspect of the present invention, there isprovided a washing method including: performing washing by alternatelyrotating the pulsator in both directions; allowing a spray nozzle tospray wash water into the inner tub after the wash water circulates outof the outer tub and passes through a filter provided on a circulationpassage in a forward direction; and allowing the wash water drained outof the outer tub to pass through the filter in a reverse direction anddrain out of a washing machine so that foreign substances collected inthe filter can be exhausted out of the washing machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a side sectional view of a washing machine according to anexemplary embodiment of the present invention;

FIG. 2 is a schematic view of a major part of the washing machine of theexemplary embodiment of the present invention, illustrating a processfor filtering out foreign substances from the wash water circulating ina circulation passage;

FIG. 3 is a schematic view of a major part of the washing machine ofFIG. 2, illustrating a process for cleaning the filter;

FIG. 4 is a schematic view of a major part of a washing machineaccording to another exemplary embodiment of the present invention,illustrating a process for filtering out the foreign substances fromwash water circulating in a circulation passage;

FIG. 5 is a schematic view of a major part of the washing machine ofFIG. 4, illustrating a process for cleaning the filter;

FIG. 6 is a flowchart illustrating a washing method according to anexemplary embodiment of the present invention;

FIG. 7 is a perspective view of a balancer and a dynamic vibrationabsorber that can be applied to the washing machine of FIG. 1 accordingto an exemplary embodiment of the present invention;

FIG. 8 is a sectional view taken along line A-A of FIG. 7;

FIG. 9 is a partially enlarged view of FIG. 8;

FIG. 10 is an exploded perspective view of FIG. 7;

FIG. 11 is a sectional view of a washing machine according to anotherexemplary embodiment of the present invention;

FIG. 12 is a plane view of the washing machine of FIG. 11, with a topcover removed;

FIG. 13 is a partial sectional view of a lower side portion of thewashing machine of FIG. 11;

FIG. 14 is a view of an inner tub and balancer illustrated in FIG. 11;

FIG. 15 is a perspective view of a lower balancer and fixing bracketillustrated in FIG. 14;

FIG. 16 is a partial sectional view of a lower balancer and inner tubillustrated in FIG. 14; and

FIG. 17 is a flowchart illustrating a method for assembling the outertub of the washing machine of FIG. 11 according to an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The foregoing and other features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings. Exemplary embodiments of the present inventionwill now be described in detail with reference to the accompanyingdrawings. The invention may, however, be embodied in many differentforms and should not be construed as being limited to the embodimentsset forth herein. Rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. In the drawings, theshapes and dimensions may be exaggerated for clarity, and the samereference numerals will be used throughout to designate the same or likecomponents.

Hereinafter, exemplary embodiment of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 is a side sectional view of a washing machine according to anexemplary embodiment of the present invention. Referring to FIG. 1, awashing machine of an exemplary embodiment of the present inventionincludes a casing 1 defining an appearance of the washing machine, anouter tub 4 disposed in the casing 1, and an inner tub 5 disposed in theouter tub 4. Casing 1 includes a cabinet 1 a having an opened top and atop cover 1 b that covers the opened top of the cabinet 1 a and isprovided with a laundry loading/unloading opening through which thelaundry can be loaded and unloaded.

The outer tub 4 for storing wash water is provided in the cabinet 1 aand the inner tub 5 in which the laundry is loaded 4 is rotatablyprovided in the outer tub 4. A pulsator 6 is rotatably provided on abottom of the inner tub 5.

In addition, a driving unit 10 providing driving force for rotating theinner tub 5 and/or the pulsator 6 is provided in the cabinet 1 a. A door3 for opening and closing the laundry loading/unloading opening of thetop cover 1 b is provided on the top cover 1 b.

The wash water is supplied through a water supply passage 8 connected toan outer water source such as a water tap. A water supply valve 9 forcontrolling the supply of the wash water may be provided on the watersupply passage 8. The wash water supplied through the water supplypassage 8 is directed into the inner and outer tubs 5 and 4 via a washaid agent box 11 storing detergent, softener, whitener, and the like.Alternatively, the wash water may be may be sprayed into the inner tub 5via a spray nozzle 12 (that will be described later) without passingthrough the wash aid agent box 11. Meanwhile, the inner tub 5 isprovided with a plurality of openings through which the wash water flowsbetween the inner and outer tubs 5 and 4.

FIG. 2 is a schematic view of a major part of the washing machine of theexemplary embodiment of the present invention, illustrating a processfor filtering out foreign substances from the wash water circulating ina circulation passage. Referring to FIG. 2, the washing machine of theexemplary embodiment of the present invention further includes a spraynozzle 12 for spraying the wash water into the inner tub 5, acirculation passage 17 connecting the outer tub 4 to the spray nozzle12, a filter 16 for collecting foreign substances such as lint and thelike suspended in the wash water, a first pump 14 that pumps out thewash water such that the wash water is directed to the spray nozzle 12along the circulation passage 17 and sprayed into the inner tub 5, adrain passage 19 having a first end connected to the outer tub 4 and asecond end connected to the circulation passage 17 between the spraynozzle 12 and the first pump 14, and a second pump 18 for draining thewash water from which the foreign substances are removed by the filter16.

Hereinafter, the first pump 14 will be referred to as “circulation pump”as it allows the wash water drained from the outer tub 4 to be sprayedinto the inner tub 5 through the spray nozzle 12 via the circulationpassage 17. The second pump 18 will be referred to as “drain pump” as itis configured to drain the wash water stored in the outer tub 4 out ofthe washing machine.

In addition, the washing machine may further include a first valve 21for controlling the wash water flowing from the outer tub 4 into thecirculation passage 17, a second valve 23 for controlling the wash waterflowing from the circulation passage 17 into the circulation pump 14, athird valve 22 for controlling the wash water flowing into thecirculation passage 17 through the drain passage 19. Here, a valve (notshown) may be further provided on a connecting portion between the outertub 4 and the drain passage 19 to prevent the wash water from remainingin the drain passage 19.

In the washing machine according to the exemplary embodiment of thepresent invention, when the water supply valve 9 is opened, the washwater is supplied into the inner and outer tubs 5 and 4 through thewater supply passage 8 via the wash aid agent box 11. When the washwater fills in the outer tub 5 to a predetermined water level, the innertub 5 and/or the pulsator 6 rotates to perform the washing. During thiswashing, wash water circulation is realized by draining the wash waterout of the outer tub 4 and spraying the drained wash water into theinner tub 5 through the spraying nozzle 12. To realize this, the firstvalve 21 is opened and the circulation pump 14 operates.

Here, describing the process of the wash water circulation in moredetail, the wash water directed from the outer tub 4 into thecirculation passage 17 is sprayed into the inner tub 12 via the filter16, the circulation pump 14, and the spray nozzle 12 in this order. Whenthe wash water passes through the filter 16, the foreign substances suchas the lint and the like suspended in the water are filtered out by thefilter 16.

Meanwhile, while the circulation pump 14 operates, the pulsator 6 mayalternately rotate in both directions to perform agitation washing. Atthis point, the driving unit 10 may be driven such that the pulsator 6rotates shortly in one direction in one rotation cycle and rotatesshortly in the other direction within the one rotational cycle.

In the washing machine according to the exemplary embodiment of thepresent invention, the washing is realized by rotating the inner tub 5or the pulsator 6 in a variety of patterns. When the pulsator 6 rotates,foreign substances such as lint and the like are removed from thelaundry by friction between the pulsator 6 and the laundry and suspendedin the wash water. The foreign substances are effectively collected bythe filter 16 during the circulation of the wash water through thecirculation passage 17.

FIG. 3 is a schematic view of a major part of the washing machine ofFIG. 2, illustrating a process for cleaning the filter 16. Referring toFIG. 3, in the washing machine of the exemplary embodiment of thepresent invention, in order to exhaust the foreign substances collectedby the filter 16 together with the wash water that is being drained, thewash water drained from the outer tub 4 passes through the filter 16 ina reverse direction when draining the wash water outer of the washingmachine. Here, defining the direction in which the wash water passesthrough the filter 16, as shown in FIG. 2, as the direction in which thewash water passes through the filter 16 so that the foreign substancesare collected in the filter 16 is defined as a forward direction. On theother hand, as shown in FIG. 3, the direction in which the wash waterpasses through the filter 16 so that the foreign substances collected inthe filter 16 can be exhausted outside of the washing machine is definedas the reverse direction.

When the wash water is drained while passing through the filter 16 inthe reverse direction, the foreign substances collected in the filter 16are exhausted out of the washing machine together with the wash waterthat is being drained out of the washing machine. At this point, thethird valve 22 is opened so that the wash water drained from the outertub 4 is introduced into the circulation passage 17 through the drainpassage 19. In addition, the second valve 23 is opened so that the washwater is introduced into the drain pump 18 through the circulationpassage 17, after which the drain pump 18 is operated. Meanwhile, whendraining the wash water, it can be considered to open not only the thirdvalve 22 but also the first valve 21. In this case, the draining timecan be shortened.

In addition, as shown in FIG. 3, when draining the wash water in theouter tub 4 out of the washing machine, the inner tub 5 may continuouslyrotate in a direction. At this point, an RPM of the inner tub 5 may be adegree at which the laundry m is attached to the inner wall of the innertub 5 to rotate together with the inner tub 5 by centrifugal force. Inthis case, a certain amount of the water contained in the laundry m isremoved from the laundry m by the centrifugal force and is drained.

Meanwhile, while the wash water is drained out of the washing machine,it can be also considered to spray the wash water into the inner tub 5through the spray nozzle 12 to rinse the laundry m. For this, a passage(not shown) connecting the spray nozzle 12 to the water supply passage 8may be formed. While the wash water in the outer tub 4 is drained out ofthe washing machine, the wash water is sprayed through the spray nozzle12 and, at the same time, the inner tub 5 may continuously rotate in onedirection. The wash water sprayed from the spray nozzle 12 is uniformlysoaked in the laundry and thus the rinsing can be effectively realized.The water removed from the laundry m by the centrifugal force iscontinuously drained to the outer tub 4 through the openings formedthrough the inner tub 5 and thus the recontamination of the laundry bythe wash water used for rinsing can be prevented. At this point, inorder for the laundry to adhere to the inner wall of the inner tub 5 andintegrally rotate together with the inner tub 5, the inner tub 5 mayrotate at an RPM at which the centrifugal force can be sufficientlygenerated.

FIG. 4 is a schematic view of a major part of a washing machineaccording to another exemplary embodiment of the present invention,illustrating a process for filtering out the foreign substances from thewash water circulating in the circulation passage 17. FIG. 5 is aschematic view of a major part of the washing machine of FIG. 4,illustrating a process for cleaning the filter 16.

In the washing machine of this exemplary embodiment of the presentinvention, a process for allowing the wash water to pass through thefilter 16 in the forward direction so that the foreign substancessuspended in the wash water can be filtered out by the filter 16 is thesame as the exemplary embodiment described with reference to FIG. 2 andthe process for allowing the wash water to pass through the filter 16 inthe reverse direction so as to clean the filter 16 is the same as theexemplary embodiment described with reference to FIG. 3.

However, the washing machine of this exemplary embodiment of the presentinvention is different from the washing machine of the foregoingexemplary embodiment in that the circulation and draining of the washwater are realized by one pump 28. In this exemplary embodiment, sincethe circulation and draining of the wash water is selectively realizedby one pump 28, the pump 28 will be referred to as “circulation/drainpump,” hereinafter.

The washing machine of this exemplary embodiment will be describedhereinafter while omitting the description of components that are sameas those of FIGS. 2 and 3.

Referring to FIG. 4, in this exemplary embodiment, in order to collectthe foreign substances suspended in the wash water using the filter 16,the wash water in the outer tub 4 is circulated to the circulationpassage 17 and is directed to the spray nozzle 12 while passing throughthe filter 16 in the forward direction. At this point, thecirculation/drain pump 28 pumps out the wash water such that the washwater can be sprayed through the spray nozzle 12 via the circulationpassage 17.

Referring to FIG. 5, when draining the wash water out of the outer tub4, the circulation/drain pump 28 is operated such that the wash waterdrained from the outer tub 4 can pass through the filter 16 in thereverse direction. The circulation/drain pump 28 may include an impellerdriven by a motor. The circulation and draining of the wash water may bedetermined in accordance with the rotational direction of the impeller.

That is, the forward direction may be defined as the direction in whichthe impeller rotates such that the wash water passes through the filter16 in the direction shown in FIG. 4. Where the reverse direction may bedefined as the direction in which the impeller rotates such that thewash water passes through the filter 16 as shown in FIG. 5.

According to the washing machine of this exemplary embodiment, the washwater is circulated or drained by one circulation/drain pump 28. Whenthe wash water is circulated, the foreign substances contained in thewash water are collected by the filter 16. When the wash water isdrained, the foreign substances collected in the filter 16 are exhaustedout of the washing machine.

FIG. 6 is a flowchart illustrating a washing method according to anexemplary embodiment of the present invention.

Referring to FIG. 6, in the washing machine of the present invention, anagitating washing at S11 may be performed by alternately rotating thepulsator 6 in clockwise and counter-clockwise directions in a shortcycle (hereinafter, referred to as “agitating washing”). In order forthe filter 16 to collect the foreign substances such as lint and thelike that are removed from the laundry and suspended in the wash waterduring the agitating washing step S11, the wash water in the outer tub 4is circulated to the circulation passage 17 at S12 such that the washwater is sprayed into the inner tub 5 through the spray nozzle 12 afterpassing through the filter 16 in the forward direction (hereinafter,referred to as “wash water circulation”).

During the agitating washing step S11, the driving unit 10 may be drivensuch that the pulsator 6 rotates shortly in one direction in onerotation cycle and rotates shortly in the other direction within the onerotational cycle.

In the wash water circulation step S12, the wash water is drained fromthe outer tub 4 to the circulation passage 17 and sprayed through thespray nozzle 12 after passing through the filter 16 in the forwarddirection by the pump. At this point, the first valve 21 is opened andthe second and third valves 23 and 22 are closed.

In a draining step S13, the wash water drained from the outer tub 4 tothe draining passage 19 passes through the filter 16 in the reversedirection along the circulation passage 17, after which the wash wateris drained out of the washing machine. In the draining step S13, thewash water may be sprayed through the spray nozzle 12 through a passage(not shown) branched off from the water supply passage 8. At this point,the inner tub 5 may continuously rotate in a direction at an RPM atwhich the laundry m is attached to the inner wall of the inner tub 5 torotate together with the inner tub 5 by centrifugal force.

According to the washing machine and washing method that are describedwith reference to FIGS. 1 to 6, because the filter is automaticallycleaned during the draining, there is no need for a user to clean thefilter. In addition, because the filter is frequently cleaned, a cleanedstate is always maintained.

FIG. 7 is a perspective view of a balancer 30 and a dynamic vibrationabsorber 20 that can be applied to the washing machine of FIG. 1according to an exemplary embodiment of the present invention. FIG. 8 isa sectional view taken along line A-A of FIG. 7. FIG. 9 is a partiallyenlarged view of FIG. 8. FIG. 10 is an exploded perspective view of FIG.7.

The following will describe the dynamic vibration absorber 20 forabsorbing vibration generated when the inner tub 5 rotates withreference to FIGS. 7 to 10. The dynamic vibration absorber 20 is amass-elastometer provided on the inner tub 5 to attenuate the vibrationof the inner tub 5. The dynamic vibration absorber 20 includes avibration body (or a mass body) 22 that absorbs the vibration, which isgenerated when the inner tub 5 rotates, and vibrates by itself and anelastic body 23 elastically supporting the vibration body 22.

The vibration body 22 is formed in a circular shape and provided along acircumference of the inner tub 5. The elastic body 23 elasticallysupports the vibration body 22. Since the dynamic vibration absorber 20is formed in the circular shape, it can effectively absorb the vibrationregardless of the vibration direction of the inner tub 5.

The vibration body 22 may be provided on any one of the inner or outercircumferences of the inner tub 5. In order to maintain a sufficientspace between the inner and outer tubs 5 and 4, the vibration body 22may be provided on the inner circumference of the inner tub 5.

The dynamic vibration absorber 20 may further include a receivingportion 21 extending along the circumference of the inner tub 5. Thevibration body 22 and the elastic body 23 are received in the receivingportion 21.

Likewise the vibration body 22, the elastic body 23 is formed in acircular shape and provided with a circular opening in which thevibration body 22 can be inserted.

The vibration body 22 may be formed of high density metal and theelastic body 23 may be formed of rubber or synthetic resin havingelastic force.

Meanwhile, the balancer 30 may be provided on an upper portion of theinner tub 5 (see FIG. 1). Liquid is filled in the balancer 30. When theinner tub 5 rotates, the liquid in the balancer 30 is positioned in anopposite direction to a weight center of the inner tub 5 to compensatethe unbalance. The receiving portion 21 may be coupled to an innercircumference of the balancer 30. Accordingly, a space for receiving thevibration body 22 and the elastic body 23 is formed between the innercircumference of the balancer 30 and the receiving portion 21.

The balancer 30 may be formed along any one of the inner or outercircumferences of the inner tub 5. Hereinafter, a case where the dynamicvibration absorber 20 is provided along the inner circumference of thebalancer 30 will be exemplarily described.

When the inner tub 5 rotates and generates the vibration, the vibrationbody 22 also vibrates. At this point, since some of the energy excitingthe vibration of the inner tub 5 is consumed to vibrate the vibrationbody 22, the vibration of the inner tub 5 is gradually attenuated. Thatis, since some of the vibration energy of the whole system is absorbedin the dynamic vibration absorber 20, the vibration of the inner tub 5is reduced.

The elastic body 23 is elastically deformed as the vibration body 22vibrates. Since the inner tub 5 is a rigid body that rotates and theelastic body 23 and the vibration body 22 are provided on the inner tub5 that is the rigid body, the force applied from the elastic body 23 tothe vibration body 22 acts in an opposite direction to the vibrationforce of the inner tub 5. Accordingly, the vibration of the inner tub 5is not excited by the vibration of the vibration body 22 but reduced.

When it is assumed that the natural frequency of the inner tub 5 is w1and the resonant frequency of the inner tub 5 without the dynamicvibration absorber 20 is w0, the resonant frequency of the inner tub 5with the dynamic vibration absorber 20 may be separated into w0′ andw0″. Accordingly, in the washing machine of the exemplary embodiment ofthe present invention, no resonant phenomenon occurs even when thevibration of the inner tub 5 is excited with the frequency w0. Needlessto say, the inner tub 5 is designed such that an operational frequencyof the inner tub 5 avoids the frequencies w0′ and w0″.

Since the vibration generated when the inner tub 5 rotates can bereduced by the dynamic vibration absorber 20, the inner tub 5 can stablyrotate. Accordingly, since the uniform space can be maintained betweenthe inner and outer tubs 5 and 4, collisions between the inner and outertubs 5 and 4 may be prevented. In addition, the tub 5 can be rotated ata higher RPM during spinning

FIG. 11 is a sectional view of a washing machine according to anotherexemplary embodiment of the present invention. FIG. 12 is a plane viewof the washing machine of FIG. 11, with a top cover removed. FIG. 13 isa partial sectional view of a lower side portion of the washing machineof FIG. 11.

As shown in FIGS. 11 and 12, in order to more accurately describe thewashing machine, a length direction Y, a horizontal direction X normalto the length direction Y, a vertical direction Z normal to the lengthand horizontal directions Y and X are denoted with reference to thewashing machine.

The washing machine of FIG. 11 is a top-loading type washing machine inwhich an inner tub 5 rotates about a vertical axis. An outer tub 4 issuspended on the casing 1 by a plurality of suspensions 100.

Each suspension 100 includes a supporting rod 110 and a damper 120. Thesupporting rod 110 is for suspending the outer tub 4 on the casing 1,having a first end connected to the casing 1 through a first supportingpart 200 and a second end connected to the outer tub 4 by the damper 120and a second supporting part 300.

The damper 120 damps vibrations of the outer tub 4 during the operationof the washing machine. The damper 120 is fixed on an outer-lower sideportion of the outer tub 4 by the second supporting part 300 provided onthe outer-lower side portion of the outer tub 4.

Suspensions 100 are aligned in a vertical direction in parallel witheach other. Accordingly, the supporting rods 110 and the dampers 120 arealigned in the vertical direction in parallel with the verticaldirection. Generally, during the rotation of the inner tub 5, horizontalcomponents in the horizontal direction X or the length direction Y maybe generated by a variety of factors such as unbalancing of the laundryloaded in the inner tub 5, an RPM or resonant property of the inner tub5, and the like.

According to the washing machine of this exemplary embodiment, since thesuspensions 100 are aligned in the vertical direction Z parallel witheach other, the horizontal component caused by the vibration of theouter tub 4 can be reduced and thus the amplitude in the horizontaldirection X or the length direction Y can be reduced. Accordingly, adiameter D of the outer tub 4 can be enlarged and thus the laundryloading volume can be increased.

As the suspensions 100 are aligned in the vertical direction parallelwith each other, as shown in FIG. 12, the first supporting part 200supporting the first end of the suspension 100 and the second supportingpart 300 supporting the second end of the suspension 100 may be disposedto at least partly overlap with each other when viewed from the top.

Meanwhile, in order to align the suspensions 100 in the verticaldirection parallel with each other, the second supporting part 300 mayinclude an extending portion 305 that fixes the damper 120 to the outerside portion of the outer tub 4 such that the damper 120 is spaced apartfrom the outer side portion of the outer tub 4 by a predetermineddistance.

As shown in FIG. 13, the second supporting part 300 may include areinforcing portion 310 formed in a blade shape to enhance strength andreliably fix the suspension 100 to the outer tub 4. The reinforcingportion 310 may be integrally formed with the outer tub 4 or separatelyformed and coupled to the outer tub 4. The reinforcing portion 310 maybe a rib that extends in a vertical direction and is connected to theside portion of the outer tub 4.

FIG. 14 is a view of the inner tub 5 and balancer 30 illustrated in FIG.11 and FIG. 15 is a perspective view of a lower balancer 52 and fixingbracket 53 illustrated in FIG. 14. FIG. 16 is a partial sectional viewof the lower balancer 52 and inner tub 5 illustrated in FIG. 14.

At least one balancer 30, 52 may be installed on the inner tub 5 toprevent the unbalancing of the inner tub 5 or the generation ofvibrations caused by unevenly loaded laundry.

In the present invention, the balancers 30, 52 are disposed at upper andlower portions. That is, the balancers may be defined as an upperbalancer 30 disposed at the upper portion of the inner tub 5 and a lowerbalancer 52 disposed at the lower portion of the inner tub 5.

In one embodiment, the upper balancer 30 may be a hydraulic balancer inwhich a liquid is filled and the lower balancer 52 may be a ballbalancer having a ball 52 a. The hydraulic balancer may be filled withthe liquid to generate a distributed load while the ball balancer maygenerate a concentrated load as the ball is forced in a sidewaysdirection.

Accordingly, in order to minimize a rotational moment generated by theconcentrated load of the ball balancer, the ball balancer may bedisposed at a location closer to a weight center G of the inner tub 5than the liquid balancer.

That is, a spaced distance dl in a vertical direction between the weightcenter G of the inner tub 5 and the ball balancer 52 may be less than aspaced distance d2 in a vertical direction between the weight center Gof the inner tub 5 and the hydraulic balancer 30.

Since the weight center G of the inner tub 5 is located at the lowerportion of the inner tub 5, the ball balancer may preferably be used asthe lower balancer 52 and the liquid balancer may preferably be used asthe upper balancer 30.

In addition, since the upper balancer 30 is disposed at the upperportion of the inner tub 5, when the thickness of the upper balancer 30in the vertical direction is reduced, the utilization of the inner spaceof the washing machine may be increased.

In this exemplary embodiment, since both the lower balancer 52 and theupper balancer 30 are provided, the thickness of the upper balancer 30in the vertical direction can be reduced as compared with the prior art.

In addition, a width w2 in a radial direction of the upper balancer 30may be equal to a width w1 in the radial direction of the lower balancer52. At this point, the thickness t2 in the vertical direction of thebalancer 30 may be less than the thickness t1 in the vertical directionof the lower balancer 52. As the thickness of the upper balancer 30 inthe vertical direction is reduced, the utilization of the inner space ofthe washing machine may be increased and thus the volume of the washingmachine can be increased as compared with the prior art.

The upper balancer 30 may be formed in a ring shape and is filled with aliquid such as salt water or the like.

The upper balancer 30 may be coupled to the upper portion of the innertub 5 by a coupling member.

The lower balancer 52 may be formed in a ring shape. A plurality of theballs 52 a may be disposed in the lower balancer 52. The lower balancer52 may be filled with silicon oil to allow the balls 52 a to smoothlymove therein.

Meanwhile, referring to FIGS. 14 and 16, the lower balancer 52 may becoupled to the lower portion of the inner tub 5 by a fixing bracket 53.

The fixing bracket 53 may be formed in a ring shape corresponding to thelower balancer 52 and configured to support a lower portion of the lowerbalancer 52.

The fixing bracket 53 may have a first flange portion 53 a that isformed on an outer circumferential surface and bent upward so that theouter circumferential surface of the fixing bracket 53 encloses an outercircumferential surface of the lower balancer 52.

The fixing bracket 53 may have a second flange portion 53 b that isformed on an inner circumferential surface and bent upward so that theinner circumferential surface of the fixing bracket 53 encloses an innercircumferential surface of the lower balancer 52.

The flange portion 53 b may be formed in a shape corresponding to alower-outer wall of the inner tub 5. The second flange portion 53 b maybe formed at a plurality of locations that are spaced apart from theinner circumferential surface of the fixing bracket 53 by apredetermined distance.

The second flange portion 53 b may be coupled to the lower-outer wall ofthe inner tub 5 by a coupling member such as a screw or the like.

As described above, as the upper and lower balancers are respectivelydisposed at the upper and lower portions of the inner tub 5 anddifferent types of the upper and lower balancers are used, the vibrationcan be more effectively reduced.

In addition, the volume of the liquid balancer that is the upperbalancer can be more reduced than the prior art.

Further, since the ball balancer is disposed at the lower portion of theinner tub 5, it may be closer to the center of the inner tub 5 and thusthe rotational moment can be reduced.

FIG. 17 is a flowchart illustrating a method for assembling the outertub of the washing machine of FIG. 11 according to an exemplaryembodiment of the present invention.

Referring to FIG. 17, a method for assembling the outer tub includesinserting the outer tub 4 into the casing 1 (S17), assembling the firstsupporting part 200 on the casing 1 (S18), and suspending thesuspensions 100 on the first supporting part 200 (S19). At this point,the suspensions 100 are disposed in the vertical direction in parallelwith each other.

That is, for the prior art washing machine, the outer tub 4 is insertedin the casing 1 after the first supporting part 200 is assembled on thecasing 1, after which the suspensions 100 are suspended on the firstsupporting part 200. Therefore, it is difficult to align the suspensions100 in the vertical direction in parallel with each other. Accordingly,the suspensions are not aligned in the vertical direction and thus thevibration in the horizontal direction of the outer tub 4 cannot beeffectively attenuated when the washing machine operates.

As the washing machine is manufactured in accordance with theabove-described assembling method of the exemplary embodiment of thepresent invention, the suspensions 100 can be aligned in the verticaldirection in parallel with each other. Accordingly, the horizontalcomponent of the vibration of the outer tub 4 can be effectively reducedwhen the washing machine operates. In addition, the diameter of theouter tub 4 can be increased by the reduced horizontal component, thespace utilization can be improved and the laundry loading volume can beincreased. As a result, user convenience and reliability of the washingmachine can be improved.

The effects of the present invention are not limited to the effectsdescribed above, and other effects that have not been set forth hereinwill be clearly understood from the appended claims by those skilled inthe art.

Although the preferred embodiments of the invention have been disclosedfor illustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

What is claimed is:
 1. A washing machine comprising: an outer tub forstoring wash water; an inner tub that is rotatably provided in the outertub and in which laundry is loaded; a spray nozzle configured to spraythe wash water into the inner tub; a circulation passage connecting theouter tub to the spray nozzle; a filter provided in series with thecirculation passage; a first pump that directs the wash water circulatedfrom the outer tub to the circulation passage to the spray nozzle sothat foreign substances suspended in the wash water can be collected inthe filter; a drain passage that connects the outer tub to thecirculation passage and is connected between the filter and the spraynozzle; and a second pump that directs the wash water supplied to thecirculation passage through the drain passage such that the wash waterpasses through the filter in a reverse direction and thus the foreignsubstances collected in the filter are exhausted out of the washingmachine together with the wash water.
 2. The washing machine of claim 1,further comprising: a pulsator rotatably provided in the inner tub,wherein the pulsator rotates during operation of the first pump.
 3. Thewashing machine of claim 1, wherein the pulsator alternately rotates ina clockwise and a counter-clockwise direction.
 4. The washing machine ofclaim 1, wherein the inner tub continuously rotates in one directionduring operation of the second pump.
 5. The washing machine of claim 4,the wash water is sprayed into the inner tub by the spray nozzle duringthe operation of the second pump and continuous rotation of the innertub in the one direction.
 6. The washing machine of claim 4, wherein theinner tub rotates at an RPM at which the laundry adheres to the innertub by centrifugal force and rotates together with the inner tub.
 7. Thewashing machine of claim 5, wherein the inner tub rotates at an RPM atwhich the laundry adheres to the inner tub by centrifugal force androtates together with the inner tub.
 8. The washing machine of claim 1,further comprising a first valve for controlling the wash water drainedfrom the outer tub to the circulation passage.
 9. The washing machine ofclaim 8, wherein the first valve is opened when the first pump operates.10. The washing machine of claim 1, further comprising a second valvefor controlling the wash water directed from the circulation passage tothe second pump.
 11. The washing machine of claim 10, wherein the secondvalve is opened when the second pump operates.
 12. The washing machineof claim 1, further comprising a third valve for controlling the washwater directed from the drain passage to the circulation passage. 13.The washing machine of claim 12, wherein the third valve is opened whenthe second pump operates.
 14. A washing machine comprising: an outer tubfor storing wash water; an inner tub that is rotatably provided in theouter tub and in which laundry is loaded; a spray nozzle configured tospray the wash water into the inner tub; a circulation passageconnecting the outer tub to the spray nozzle; a filter provided inseries with the circulation passage; a drain passage that connects theouter tub to the circulation passage and is connected between the filterand the spray nozzle; and a pump that directs the wash water circulatedfrom the outer tub to the circulation passage such that the wash waterpasses through the filter in a forward direction and thus foreignsubstances suspended in the wash water can be collected in the filter ordirects the wash water supplied to the circulation passage through thedrain passage such that the wash water passes through the filter in areverse direction and thus the foreign substances collected in thefilter are exhausted out of the washing machine together with the washwater.
 15. The washing machine of claim 14, further comprising: apulsator rotatably provided in the inner tub, wherein the pulsatoralternately rotates in a clockwise and a counter-clockwise directionwhen the pump operates to allow the wash water to pass through thefilter in the forward direction.
 16. The washing machine of claim 15,wherein the inner tub continuously rotates in one direction when thepump operates to allow the wash water to pass through the filter in thereverse direction.
 17. A washing method comprising: performing washingby alternately rotating the pulsator in a clockwise and acounter-clockwise direction; circulating wash water from an outer tubinto an inner tub after the wash water passes through a filter providedin series with a circulation passage in a forward direction; andallowing the wash water drained out of the outer tub to pass through thefilter in a reverse direction and drain out of a washing machine so thatforeign substances collected in the filter can be exhausted out of thewashing machine together with the wash water.
 18. The washing method ofclaim 17, wherein discharging wash water from the spray nozzle occurswhile continuously rotating the inner tub in one direction.
 19. Thewashing method of claim 18, wherein the inner tub rotates at an RPM atwhich laundry within the inner tub adheres to the inner tub bycentrifugal force and rotates together with the inner tub.
 20. Thewashing method of claim 19, wherein the circulating the wash watercomprises discharging the wash water from a spray nozzle into the innertub.